1. Field
Embodiments relate to a backlight unit.
2. Description of the Related Art
Light Emitting Diodes (LEDs) are devices which convert electric signals into light using characteristics of compound semiconductors. Such LEDs are being utilized in home appliances, remote controllers, electric bulletin boards, displays and various other automated machines and the application range thereof is gradually increasing.
A backlight unit using light emitting diodes may be used in display apparatuses, such as liquid crystal display apparatuses and also, may be used in lights in a variety of fields. In general, a backlight unit includes a light source, a light guide plate configured to diffuse light emitted from the light source, and optical sheets which function to diffuse or condense light emitted from the light guide plate.
Light emitting diodes, which are operated at a low voltage and exhibit high efficiency, are usable as the light source of the backlight unit. Such a light emitting diode is a 2-terminal device containing a compound semiconductor, such as Gallium Arsenide (GaAs), Gallium Nitride (GaN), Indium Gallium Nitride (InGaN) or the like. When power is applied to a cathode terminal and an anode terminal of the light emitting diode, the light emitting diode emits visible light generated upon electron-hole coupling.
Backlight units are classified into an edge type backlight unit and a vertical type backlight unit according to positions of light sources.
The edge type backlight unit is mainly applicable to a relatively small scale liquid crystal display apparatus, such as a monitor of a desktop computer and a laptop computer. Such an edge type backlight unit exhibits improved light uniformity and long lifespan and is advantageous to achieve a slim design of the liquid crystal display apparatus.
In the case of a backlight unit using light emitting devices, it is necessary to guide light generated from the light emitting devices in a predetermined direction and to ensure uniform light emission throughout a display region of the backlight unit. In addition, slimness and light weight of the backlight unit are important problems, in order to enhance productivity and user convenience.